


B r o t h e r s

by xXxDeadEyesNekuxXx



Category: Undertale (Video Game)
Genre: Some Fluff, Some angst, Underfell, Underfell AU, gender neutral frisk, they pronouns
Language: English
Status: Completed
Published: 2015-11-01
Updated: 2015-11-01
Packaged: 2018-04-29 08:17:26
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,373
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5121365
Author URL: https://archiveofourown.org/users/xXxDeadEyesNekuxXx/pseuds/xXxDeadEyesNekuxXx
Summary: <blockquote class="userstuff">
              <p>(Underfell AU) Sans, set with the task to either kill or capture the human ends up breaking down and being confronted by Papyrus, his brother whom he just wished would go back to being his old self. When Sans’ power threatens to erupt, will he be able to control it?</p>
            </blockquote>





	B r o t h e r s

Sans had never wanted to become a part of the royal guard. He had never wanted to work for anybody besides from himself. He wasn't the kind of guy that liked following orders unless if they fulfilled his own ambitions. It was because of Papyrus, his brother, that he had been given this role. He too was a royal guard and after many monsters had seen his power they had assumed that Sans was just as strong and therefore royal guard material.

Everyone was wrong.

Sans was not as strong is Papyrus…

He was much, much more powerful than anybody could have imagined him being. This had been learned when some thug had to be dealt with by Sans on a solo mission. He had meant to knock the guy out but instead…

Sans absolutely obliterated him. He had never meant to do such a thing. Monsters just do not kill each-other out of the blue.

After that, Sans knew that he just wasn't the same as everybody else. Hell, he was on a whole different level. But the thing that made him most scared was accidently killing his brother with the same power.

He vowed never ever to use this power again so he tried to quit the royal guard but Papyrus wouldn't allow such a thing. He kept saying that it was a waste and that Sans was just going to slack off without a real job and never get anywhere in life.

Papyrus had changed so much since joining up that Sans hardly knew him.

So Sans stayed on the royal guard, even if it made him unhappy. He never had to use his power because he just designed traps for whomever he had to capture instead of fighting them. It took more time and sometimes the monster would avoid being caught by the trap but Sans was fine with this. Even if his brother and the rest of the royal guard looked down on him because his lack of successful assignments.

Deep down, it still hurt every time his brother would give 'the look'. The one that made a person feel as if their insides (or lack of) were in pain. It was terrible but Sans was a good actor. He would just smile and shrug casually before trembling a little when Papyrus had his back turned.

Yet here Sans was, set with the mission to either kill or capture a human. A human whom the entire royal guard were tasked with. Sans, accidently, was the one to stumble upon them.

 

This human wore a blue and pink striped shirt. For some reason, they had a boot nestled in their arms with a yellow flower sprouting from it.

When the human first bumped into Sans they stumbled backwards and looked worried. They were covered in cuts and bruises that had obviously been caused by monsters rather than the land itself.

"…A royal guard…" The flower whispered to the human. They too looked worried. "F-Frisk, what should we do?"

But 'Frisk' furrowed their brow before confidently taking a step forward, recovering from their fear it seemed. Such a brave person. Such a _stupid_ person.

"Hey there!" Sans said, outstretching a hand to them. "Put 'er there!"

There was a beat of silence before wind started howling through the trees. The air itself seemed to be trying to warn the human not to proceed. But of course, they too outstretched their hand and Sans' smiled widened.

Yes, yes! Just a little more…

Their hands touched before bones sprung up from the ground and enclosed the human in a cage of them. Yet, their hands were still linked together. "You and I are gonna be great pals!"

 

Sans' right eye was glowing bright red, as it always did when he used an attack. Yet, this wasn't an actual attack, it was just a trap that he could use that caused no harm to the victim.

"D-Don't worry, Frisk! I'll get us out of this!" The flower exclaimed, glaring at the skeleton.

But Frisk merely shook their head and tightened their own grip on Sans' hand. The gesture seemed to be a silent plead to free them.

"Oh please! Did you really think we were actually gonna be pals? Heh, that's cute." Sans scoffed, rolling his one burning eye flippantly.

Frisk moved closer to the bony bars and only held onto Sans' hand tighter when he tried to break free of their hold. Inwardly, he was starting to grow desperate because he was done with the physical contact. He only did things on his own terms, not the other way around. This wasn't right!

The deadly power called away inside of him. It seemed to whisper in his head to use it and be done with this. If he killed the human and got their soul then everybody would respect him. Papyrus would especially and maybe they could be like they used to and just goof off like in the old days.

But another part of Sans knew that this wasn't a fairy-tale. He wouldn't get what he wanted through one simple act. He wouldn't get the ending that he wanted.

"Hey, hey!" The flower exclaimed, trying to grab Sans' attention. "Just let us go already, ok? We didn't do anything wrong."

Sans snorted and addressed the duo, "Oh but you did. The entire of the royal guard are after you." As an afterthought he added in a dull voice, "Orders are orders."

Yet, the flower would not accept this. "Surely you can overlook us just this once."

"I'm just doing my job." It was the truth. Even so, a strange feeling was chewing away at his core that he long since had thought he would never feel ever again.

Sans pitied the duo. He actually felt bad for them and even respected how the human refused to let go of him, as if by holding his hand he would release them. Like this act would decide between life and death.

 

The human tilted their head to the side. Their mouth was open a little and they honestly looked concerned.

That's when Sans realized that he was shaking. How had he not heard or felt his own bones rattling together? Better yet, how could he be freaking out just because one grubby human was touching him? It was pitiful. Man, he was quite a mess.

Maybe he really did deserve to be shunned by the rest of the royal guard…

"SANS!"

Upon hearing the familiar voice, Sans shook even more. It wasn't due to fear. The human and the familiar voice did not make him scared. They merely caused him to freak out which might have been worse than fear. He just couldn't deal with all of this stress.

Sans was having a breakdown. He was trying his best to stop but then his deadly power was also calling to him. It was just all too much.

He could feel the power burning away, slowly beginning to spill out even if he tried to keep it inside. He couldn't lose control. He couldn't afford to.

"There you are, Sans!" Papyrus appeared, running along the path towards them. His torn cape fluttering behind him which was the very same cape that the skeleton brothers had made together for a costume solely for Papyrus. Even now, he still wore it. "Aha! You caught the human?! YOU?!"

But Sans couldn't bring himself to feel happy, despite the praise in his brother's voice that he had missed. His power, now that it was so close to being released, blocked out such positivity from him.

"Now we can bring them back to Asgore and he might even promote us to be the head of the royal guard!"

But Papyrus's glee fell short when he realized that Sans was trembling and looked like he was in pain. It was true; he was in pure agony holding himself back.

Just a matter of time before he went 'KABOOM'.

 

"Err, Sans? You can let go of them now."

But Frisk held tight. Again, Sans’ attempts of releasing himself were foiled. Did this human want to fight? Did they actually want to die? Sans would gladly do that, if he wasn't so powerful.

Sans felt as if he were burning and he desperately tried pulling himself back together and get a good hold on that destructive force but he was freaking out too much and quite quickly losing his grip. At this rate, Papyrus would be killed along with the human in no time.

"Sans?..."

No, no… Don't come any closer.

But Papyrus couldn't read minds and walked over before bobbing down a bit so he was on Sans' level. For once, he actually looked concerned and that made Sans feel a bit better. It helped him hold the power in better, even if it was just a little.

All Frisk seemed to be doing was watching them both, which was a little unnerving. Yet, they still did not let go.

"You look absolutely dreadful." Papyrus said. It wasn't an insult, it was a fact. Sans certainly felt horrible.

"Heh, I know." Sans agreed, grinning but he was sure it looked more like a grimace. He felt awfully tired.

Papyrus 'hmmed' and put a hand to Sans' forehead as if to check his temperature. "You're shaking a lot. Maybe you should leave the human to me and take a nap. This trap must have taken out all your energy."

_Oh, if only you knew._

Sans felt a bit of anger flare up. As if his brother even cared. All he wanted was the human so he could get a fancy promotion. It was sickening.

With his free hand, Sans battered away Papyrus' and glared at him with so much fury that Papyrus actually looked hurt. It did serve him right for doing the same thing to Sans for so long.

"Just leave." Sans told him coldly. "This is none of your business."

As expected, Papyrus got angry and retorted, "After everything I've done for you I can't believe that you would betray me and steal the promotion I've dreamed of having! You're so SELFISH!"

"'Done to' not 'done for', right? You've never done anything for me. All you've ever done is used and made me feel miserable." Sans replied. "I hate my job, I hate the other monsters, I even hate my life and it's all your fault. I never wanted to be a royal guard! I was happier doing nothing at all but nooo, you had to ruin that for me because you think you know what's best for me." There was a pause before the final blow was delivered, "Well, I'm sick of it and I'm sick of you. Go back to the castle without me because I'm DONE with being one of Asgore's dogs!"

 

Papyrus was still. He appeared to be in shock from Sans' words.

Sans did not feel the slightest bit guilty. He actually felt better for getting it all off of his chest and into the air. As if a sign, his power didn't feel as if it would erupt. For now, it was back under lock and key.

Slowly, Papyrus backed away before turning around, his back to his brother. "I-If you do this then…" He sounded upset. "You'll be seen as a…"

"Traitor. Yeah." Sans finished for him.

Papyrus seemed to nod to himself. He just stood there for a while, back hunched, before walking away. He didn't say another word.

 

When he was finally out of sight, Sans felt his hand be released and he turned to look at the human.

"…We're sorry about causing this…" The flower said. It seemed that Frisk wasn't a talker.

Sans stuffed his hands in the pockets of his jumper and looked away. "You didn't. I… I needed to say something sooner or later." Otherwise he may have lost control.

"We're still sorry about it anyway. Oh, I should properly introduce ourselves first."

"Sure. I'm Sans." Oddly enough, he felt as if everything was going to be ok which was weird. Nothing ever good happened once you were seen as a traitor.

"Nice to meet you! I'm Flowey the Flower and my good friend holding me is named Frisk!"

Frisk waved a little with their free hand, the one that had been holding Sans'.

Sans looked at the two of them. They both looked as if they had been through hell and back what with all the bruises and cuts on them. What an odd pair. At least they had each-other in this cruel world.

"You should come with us." Flowey suggested. "Our mission is to get through the barrier so Frisk can go home."

Considering the amount of monsters after the duo, Sans guessed that they wouldn't make it very far. Not alone, at least. But if they had some help? Maybe they had a chance.

"I might as well," Sans replied with a shrug. "-got nothing better to do."

The grins that he received were worth it. So he snapped his fingers and the bones around them disappeared without a trace that they had ever even been there.

So what if he was now considered to be a traitor? He felt happier than he had ever been back when he was a royal guard. That had to be worth the risk, even if someday soon he knew he would have to fight his brother. For now, he was content with the choices he had made and the two new friends as well.

 

Perhaps when Sans did finally fight his brother, he would regret his choices, regret not trying to patch things up. Perhaps he would die protecting the human or kill his brother. Or maybe Papyrus would be the one to kill him, or even the one to protect him from the wrath of the other monsters.

But perhaps, when the time comes, they would patch things up and both dutifully stay by the human's side until the very end, until they achieved their ultimate goal.

There were so many possibilities, so many ways for things to end. Sans just hoped that he and his brother would get the right ending. The one they deserved.

**Author's Note:**

> Just recently got into Undertale so I wrote this because the art for the 'Underfell AU' is awesome.


End file.
